(1) Field of the Invention
The present invention relates to an apparatus and method for cleaning oil wells, and more particularly to the cleaning of an oil well casing's perforation zone. Persons engaged in oil well production have ordinary skill in this art.
(2) Description of the Related Art
In a typical oil well bore from which fluids are produced from an underground formation, a cylindrical well casing is used. A well casing has perforations at one or more production zones through which fluid passes from a formation into the well casing. The flow of desired fluid through the perforations carries with it sediment and chemical contaminants. Over a period of time, sediment and chemical contaminants can clog or plug the perforations, and can also attach to the well casing. The accumulation of matter at the perforation zone and on the well casing causes a loss of production capacity from the well.
Those in the well production business have devised various tools which clean the well bore and the perforation zones.
Some tools use high pressure jets or pressure zones to clean the well bore such as described in U.S. Pat. Nos. 2,918,973 to Ozinga and 5,161,612 to Stafford. Other tools use mechanical means to clean the perforation zone such as described in U.S. Pat. Nos. 4,671,355 to Strange and 4,892,145 to Stafford.